German Patent Application No. 38 12 182 describes an ultrasound transducer with a cylinder-shaped body; to attach it, this body is inserted through a bore in a bumper of a motor vehicle and secured from falling out, from the back, using a resilient element. It has been shown that such an element can only be installed in a restricted installation angle relative to the wall. Different vehicle types, however, can have various angles of inclination relative to the road surface, so that different attachment elements might be necessary, depending on the vehicle type. However, producing these different attachment elements increases the production and warehousing costs and is therefore undesirable. Furthermore, it is disadvantageous that the removal of the attachment element with the body can be quite difficult and time-consuming.
Great Britain Patent Application No. 679 441 describes an attachment clip with which electronic components such as coils, switches, etc., can be attached to a carrier plate. The attachment clip consists of a spring part which is pushed through the carrier plate through corresponding openings. The component to be attached is pushed into the springs of the attachment clip, which have been pushed through, from the opposite side of the carrier plate, and locked in place with catch projections. To remove the component, the catch projections must be lifted up with a special tool to release these catch projections from the component.
Great Britain Patent Application No. 1 581 773 describes an attachment ring or locking ring, in which resilient hooks can be caught into corresponding teeth of a body. To attach the body in a bore of a plate, the attachment clip or locking ring is first pushed onto the body until head contact is made. Then, the body is pushed into the prepared opening of the plate, against the pressure of the resilient hooks. The body is released by being pushed out against the spring pressure of the hooks from the rear.